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It's really pretty simple. A set of strips of aluminum (or other metal) of gradually decreasing lengths, nested around pivots on each side (see the open photo). Each strip has a lip on the outside which engages a lip on the inside of the strip that surrounds it, so as you pull one over it catches the next and so on. The innermost has a handle for convenient opening and closing. The rounded ends both let them rotate smoothly and keep you from jabbing yourself on a sharp corner.

Affix the whole mechanism to a cheeseboard/breadboard and you're done.

Of course the devil is in the details, but that should give you the essentials to start experimenting with. DO NOT attempt to use the metal from soda cans; that's much too thin.